[Transverse reductional anomaly and atypical fibrodysplasia ossificans progressiva: A case diagnosed late]. / Anomalie réductionnelle transverse et fibrodysplasie ossifiante progressive atypique, à propos d'un cas de diagnostic tardif.

Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by the association of congenital bone abnormalities and extraskeletal ossification flare-ups occurring in muscles and fasciae. Early diagnosis is important to prevent ossification flare-ups, but some atypical presentations can lead to errors in diagnosis and therefore delay. Here, we report on a case of an atypical presentation of FOP in a girl, in whom prominent transverse reductional abnormalities delayed diagnosis. The patient developed extraskeletal ossifications and progressive fibrosis that led to motor restrictions. Since early diagnosis is important, we discuss the clinical presentations of FOP and the differential diagnoses.